Hydrocarbon oil



FI SSUE' XP, REF/(M943.

Patented Mar. 6, 1945 E. I. du Pont de Nem'ours & Company,-Wilmington, Del., acorporation of Delaware No Drawing, Application August 3, 1943, 7

Serial No. 497,216

10 Claims. (cl. 252-51) This invention relates to hydrocarbon oils and particularly to mineral oil compositions having low pour points and high stability against breakdown under oxidizing conditions.

Hydrocarbon oils, derived from paraflin ,and mixed base crude oils, contain an appreciable amount of paraflin wax which causes the oil to solidify at low temperatures and, in the case lubricating oils, prevent efilcient flow of the lubricants to moving parts. In the low viscosity rmmeraljoils, such as those boiling above the kerosenerange and used as fuels in compressionignition" engines, the presence of waxmaycause .iic'gui etie of the oil in, storage 'tanksiat'flow stantial amount of wax in the oil.

temperatures. Such war may? be" removed j'by; 1"

fetid settling or by dilution wane ow boiling lnaphtha ri'ollowe'db chilling and centrifuging ,cr'n1trat1on. These processes of 'rem oving tlie wax are expensive and may, if complete removal oi the wax is effected, result in a lubricant with factory combustion characteristics. j Accordin 'ly, it is generally desirable to reduce the'pour point of the oil and improve its flow characteristics at low temperature while retaining a sub 1Many materials have been proposed for addition'to lubricating oils to reduce their pour points and to improve their flow characteristics at low temperatures. Such materials include condensa'tion products of aromatic hydrocarbons'with chlorinated paraflin wax, mixed aryl 'alkyl ketones, and fatty acids and their salts" and esters. Such materials act with varying degrees of efficiency indepressing the pour points of the oils, but generally have no beneficial effect on any of the other properties of the lubricants.

Under conditions of service which are found in 'incdem automobile engines, oils tend to oxidize and form sludge which deposits on engine parts or to form corrosive products which seriously attack alloy bearings. 'Many materials have been added to oils to reduce their tendency toward deterioration, but such materials generally have no beneficial efiect on other properties of the oils.

- It is an object of the present invention to provide hydrocarbon Oils with reduced Pour points and improved flow characteristics at low temperatures. Another object of my invention is to provide lubricants which will have improved stability, as well as improved pour point characteristics. A further object is to provide new and improved pour point depressant compositions for '20 a reduced viscosity index or a fuelwithuns'atisaddition. to petroleum oils. A more particular If above and othergjobj'ctsf X 7 plished accordance with; invention which object of my invention is to provide hydrocarbon lubricating oils ofreduced pour point which is maintained to a. high degree under conditions of service in an engine and which have had their tendency toward the formation of engine deposits substantially reducedL' ,A still further object, isto provide a method for ,reducing the P u Pai t a d m t ie ll l li of drocarbon' oils. Other objects are to provide new compositions,off n'u'atter asst advancethe art.

Still other objects wiusppee Ihereinaiten'. 1

(av 'be "accoms, cuiajrliwigiit"ori'atlastioootvndse chain ia'r e dimetliyln g'r ups 'and'fN- -aliphsuc-as-tvrmndmedion M 1611? which form chain members with the fdiifietliylene groups by llinking througflifthe s and 4' carbon atoms of the pyrr'olidinedione j nucleus, in iwhioh" each -dimethylene groupflhas gjhydrog'en 're'placedby an aromatic "or aromatic ether radical and the N- aliphatic group contains at least 12 carbon atoms. I have found that such polymeric materials are very effective to reduce the pour points and improve the ilow characteritics oi mineral oils at' low temperatures. Atjthejfsam time,the polymeric materials improve the stability 1 of the oils and-particularly reduce the'tendency' of the oils to form objectionable deposits in" engines under conditions of service}; Furthermore; the oils, containing such polymeric" materials, show high resistance to corrosionfof' alloy' bearin The polymeric materials; to be added tothe hydrocarbon oils in accordance with myinv'ention, may be described alternatively as polymeric imicles,- having a molecular weight of at least 1000, formed byreacting 'a'c'opolymer of an olefin, having linked thereto aromatic radical either directly or through anetlier linkage, and a maleic anhyride, with a "primary aliphatic amine containing at least 12 carbon atomsln the aliphatic group. The polymeric material may also be characterized as a polymeric material having a molecular weight of 1000 or more and having, as its monomeric unit; the hypothetical addition product of an N-substituted imid of an alpha-beta unsaturated dicarboxylic acid, in which the substituent on the nitrogen atom is an aliphatic group containing at least-12 carbon atoms, with a compound having the general formula X-CH==CH-Y 5' Iran-N in ruon sris nnear clyuiericnnaterieh r wherein X is an aromatic group joined to the carbon residue, either directly or through an oxygen or sulfur atom, by a single bond and Y is a hydrogen atom or an alkyl or aryl group joined directly to the carbon residue.

The aliphatic groups, in the N-aliphatic-2,5- pyrrolidinedione nucleus, include cyclo aliphatic and branchedchain aliphatic, as well as straight chain aliphatic groups. Also, the aliphatic group may be saturated or unsaturated. Generally, it will be preferred that the aliphatic group be a hydrocarbon group, that is, one which consists group. By an alkyl"group, I mean a saturated aliphatic hydrocarbon group:

v Each of the dimethylene' groups, which forms a chain member in the'polymeric compounds, must have at least one hydrogen replaced by an arcmatic or an aromatic ether radical and preferably by an' aromaticradical. By an aromatic radical," I mean one in which the free valence belongs to a ring carbon atom of'a' benzene ring. By an aromatic ether radical,I; mean that a ring carbon atom ofa benzene ringis joinedto'a carbon Of the dimethylene group by an ether linkage or, in other. words, through oxygenor sulfur. The aromatic and aromatic ether radicals, attached' to the dimethylene group, may be substituted by elements and groups other than carbon and hydrogen. such as. chlorine, fluorine, nitro, ethoxy, isobutyloxy, ethylthiopropylthio, benzylthio, ethyl. barboxy, .hydroxy,, methyl,v ethyl, allyl, benzyl,,cyclohe xyl' and the like. Preferably, the aromatic radicals are aryl radicals. that is, radicals which consist of carbon. and hydrogen, and particularly aryl' radicals of the benzene series. By en.aryl radical of the benzene series," I mean one which'containsone and only one benzene ring.

'The preferred polymeric materials of. my invention are the styrene/N-octadecyl-maleimide and the indene/N -octadecyl-maleimideproducts.

The polymeric materials, which are to be em.- ployed in accordancewith my invention,. may be prepared by the copolymeri'zation of,an. olefinic compound, containing. an aromatic. nucleus, with the anhydrideof an alpha-beta unsaturatedacid, in a manner similar to theprocess-describedin Patent 2,047,398toVoss-et a1.,.and then. reacting such copolymer withanaliphatic primary amine containing at. least 12 carbon atoms. The. polymeric materials maybe obtained also by copolymerization of the imide of the unsaturated dibasic acid with the aromatic ring-containing olefin in a manner similar to the process described in British Patent. 505,120,. complete accepted May- 5, 1939. The preferred polymeric materials are derived from styrene, indene or coumarone/maleic anhydride copolymers and long chain aliphatic pri mary amines.

Preferablythearomaticring-containing olefin, the anhydride and the aliphatic amine are reacted together in substantially molar ratios. However,

range. of from 0.02%. to about 2.0%.

the relative proportions .of anhydride and olefin may be varied within wide limits. For example, one mole of the dicarboxylic acid anhydride may be polymerized with 3 moles of the aromatic substituted olefin or vice versa and the resulting polymers heated with the aliphatic amine in the proportion-of. one mole of the amine to each mole of the anhydride. The: polymerization may be brought about by heating, generally at temperatures of from about 50 C. to about C. The polymerization may be carried out without the use of a solvent or other diluent or may be carried out in a. suitable. inert solvent, such as benzene, xylene,.toluene, methylene chloride and the like at reflux temperatures. It will generally be desired to employ catalysts, such as barium peroxide, benzoyl peroxide and acetyl peroxide, to speedup the polymerization, although this is not always necessary. When employed, the catalysts will generally be used in concentrations ranging from'about 0.1% to about'2% byweight. Thereaction of 'theamine with theanhydride to form theimide will generally require higher tempera-- tures on the order of about C; to about 220 C.

By a" hydrocarbon oil, I mean one which has a viscosityof at least 35 seconds Saybolt at 100 F.', and intend to mc1ude-- therein oils in the fuel oil range, including" Dieselv fuels and furnace oil's, as well" as the" higher'viscosity oils, employed as lubricating oils and greases. The oils maybe solvent extracted oils' or conventionally refined oils;obtaii1ed from varihus base crude oils". They may bespeciallircompounded'oils; such asthcse containing lard oil, fish. oil, castor oil or the like. When the oils are fuel oils, designed for use in high speed Diesel engines, they may contain ignition primers, such as ethyl nitrate. The polymeric materialsmay be added to refined. oils or may be added to the oils during any suitable stage in the refining process.

The proportion of the polymeric material to be added to the oil will depend upon the effect desired, butwillgenerally lie between 0.02% and 510%. They may be employed in concentrations as high as 50%,. whereupon grease-like products .are obtained; Preferably, for my purpcse,.the

polymeric. materials will. be employed. within the Generally, the desiredeflect will be. obtained when the elymeric material. is. employed in the oil in a con.- centration ofirom about. 0.1% to. about. 0.5%.

In order to more clearly illustrate my invention, the preparation. of. representative polymeric materials and. the. results which are. obtainable by the practice of my invention,. the following.v examples are given, in which all vc uantitieaare given as parts by weight, except whereotherwisespecifically stated:

Example. I

Twenty-six and nine-tenths-parts of octadecylamine and 9.8' parts of maleic anhydride were mixed and heated to 170 C. in an oil bath until bubbling and evolution of water vapor stopped. The resulting product was mixed with 10 parts of'sty-rene, 0.3-part of benzoyl peroxide'was added, and. the mixture thoroughly stirred and then placed on a steam bath for 2. hours, heating in this period to: about 80 C. The resulting product, weight 32 parts, was somewhat gummy and resinous and could be pulled out into threads. It. was-dissolved in benzene, filtered, and the solvent. removed by evaporation on a steam bath. Tl'reiproliuctiwas readily dissclved'in oil by warmavg; uvlVti Vvi must. ti iitittiti itit not, in 0.5% concentration, lowered the pour point from 30 F. to F.

Example V Concentration, percent by weight g noinc. 5 Twenty-two parts of indene (80% pure) and i 14.7 parts of maleic anhydride were mixed, 0.5%

N I 30 by weight of benzoyl peroxide was added, and 0.35?.fffiiiiiiji::1::3::3131:::::::::::::::::::::I:; 0 the mixture heated carefully on a steam bath for 0.5 0 hour. Forty and four-tenths parts of octa- Emample I] Styrene and maleic anhydride were mixed in equimolar proportions and dissolved in xylene in suflicient quantity to form a solution. This solution, to which 1% of benzoyl peroxide (based on reaction ingredients in xylene solution) had been added, was heated to 100 C. and allowed to stand at this temperature until polymerization was complete. The resulting polymer was removed from the xylene by filtration, washed, and dried. Its molecular weight, on thebasis of viscosity measurements, .was in excess of 1000. Fifty and five-tenths parts of this polymer and 67.5 parts of octadecylamine were mixed thoroughly and heated for three hours at-210- 220 C. The reaction mass was dissolved in benzene, filtered, and the solvent removed by evap oration. Two.batches of material, prepared in the above fashion, yielded 230 parts of product. This material was dissolved in a Mid-Continent S. A. E.'20 oil to form a 33/;;% solution which was fluid when warm and grease-like when cool. The solution, tested in an S. A. E. 30 parafiin base oil, yielded the following data:

Example III In this example, a styrene-maleic anhydride polymer was used whose molecular weight, on the basis of viscosity measurements, was 2% to 3 times that of the polymer used in the preceding example. The polymer was heated with octadecylamine in the same ratios and using th same procedure as given in Example II. The final Concentration, percent by weight Pour point, F.

Lassa Example VI Ninety-three and six-tenths parts of a crude 'coumarone-indene fraction and 39.2 parts of maleic anhydride were mixed and 2 parts of henzoyl peroxide added. The temperature rose rapidly and the material became quite thick. After an hour; the product was scraped into' cold methanol and the insoluble portion was filtered and dried, yielding 73 'parts by weight of a res- Per cent by ceutby inous product. Forty-seven parts of this resin Wei ht of weight or Pour point, 8015mm active F. were heated with 59 parts of octadecylamine to ingredient 0 200 0. until bubbling ceased (about 2 hours),

30 dissolved in benzene, filtered, and the solvent re- 3 3:8 20 moved on the steam bath, yielding 81 parts of a 0.3 0.1 g tough reddish resin-like material. This material, 3;: 8: when tested in a wax-containing oil of S. A. E. 30 0.6 0.2 -10 45 grade, gave the following results. 0.1 0.23s --5 0.8 3% -12 0 Concentration, per cent by weight g 33 product, when tested in oil, yielded the following pour point data: Como] (glint??- oil polym r e P i t our po :1 Qmmmflm of polymer percent by weight F- Saybolt Universal viscosity at 100 F seconds. 322 353 Saybolt Universal viscosity at 200 F do. 53 55 30 .Viscosity index 92. 5 95 0 +3 5 These data indicate that this type of product does *5 not afiect the viscosity index adversely and, in

fact, has a small beneficial action on this char- Emample IV Using a styrene-maleic anhydride polymer similar to that in Example III, 5.34 parts of polymer were heated with 7.23 parts of hexadecylamine and worked up as in Example II, yielding 11 parts of a resinous-like, stringy product. When tested in a paraflin base S. K E; 30 oil, this prod- .Mixed and the following data obtained on the quantity of deposit formed.

Mg. deposit per 30 cc. oil

011 alone-control 231.5

Oil with 0.5% styrene/N-oct adecyl-maleimide polymer 173.6 Percent reduction in deposit 25 ations and modifications may be made therein" particularly in the polymeric materials, the proportions, the preparation of the polymeric materials and in the other ingredients in the oils with- .out departing from the spirit or scope of my invention. also be prepared from phenyl vinyl ether, alpha naphthyl vinyl ether, phenyl vinyl thioether, and beta-naphthyl vinyl ether, by reaction with an ,N-octadecyl-maleimide or N-hexadecyl-male- .imide. .Styrene/maleic anhydride decylamine and .oleylamine, yielded ,products which also showed effectiveness in reducing pour point and engine deposits, although not ,to as ,great a degree as those given in the examples;

Still other polymeric materials, which come within the scope of this invention, are as follows, all being polymers with molecular weights of at least 1000:

Coumarone/N-octadecyl-maleimide c oum-arone -indene AN '1- octadecyl-maleimide Phenyl vinyl ether/(N-octadecylhethylmaleimide Alpha-naphthyl vinyl ether/N-heptadecyl-maleimide Styrene/N- (Z-ethylhexadecyl) maleimide Indene/N- (-2 -hexadecyleicosanyl)maleimid -Phenyl vinyl thioether/N-octadecyl-maleimide {Beta naphthyl vinyl thioether/N hexadecylmaleimide Indene/N-naphthenyl-maleimide Styrene/N-naphthenyl-maleimide Stilbene/N-octaclecyl-maleimide Beta-methylstyrene/N-naphthenyl-ma1eimide Ethyl cinnamate/N-octadecyl-maleimide p-Hydroxystyrene/N-hexadecyl-citraconimide stilbene/"(N-octadecyl) chloromaleimide Sty-rene/ (N-octadecyl) phenylmaleimide The polymeric materials of my invention may be employed in oils containing other additives, such as organic phosphates or phosphites, *for example, tricresyl phosphate or tributyl phosphite; metal soaps or additives, for example, copper'naphthenate, tin oleate, copper derivatives of terpene mercaptans; sulfur-containing stabilizers, such as sulfurized sperm oil, S-alkylated 2- mercapto thiazolines, S-alkylated-'2-mercaptobenzothiazole, tetra-alkyl thiuram disulfides; with anti-ring sticking agents or with viscosity index improvin agents, such as polymerized isobutylene. Mineral oil compositions of the type described herein may be used in lubrication of internal combustion engines, for bearings sub-- For example, effective products maypolymer, heated with dodecylamine and a mixture of octa- 2,s7o,.e4s

-iected to high speedsand high pressuresrior gear lubrication .of thehypoid, spiral, or bevel types.

' for railroad rolling stock, for marine engines, and

ill)

for protective coatings on metallic surfaces subiect to.corrosion. They may be used as bases for greases and as components of fuel oils. The pour point depressants may be used as dew-axing assistants in refinery operations in connection with dewaxing solvents wherein higher oil yields and products of lower pour point are obtained. They are of particular importance in fuel oils for high speed Diesel engines since they permit the manufacture and use of fuel ilsof higherparafiin content .and improved ignition qualities.

I .claim:. 7

1. A paraflin wax-containing hydrocarbon oil having incorporated therein asmall proportion, sufiicient to reduce the pour point of .the oil, .of a linear polymeric material having a molecular weight of at least 1000 whose chain unitsaredimethylene groups and N-aliphatic-zfi-pyrrolidinedione nuclei which form chain members with the dimethylene groupsby linking through the .3 and 4 carbon atoms of .the pyrrolidinedione nucleus, in which each dimethylene group has a hydrogen replaced by a member of .the group consisting .of aromatic andanomatic ether radicals and :the .Naliphatic' group contains at least 12 carbon;atoms.-

2. A paraflin wax-containing hydrocarbon .oil

havin incorporated therein a small proportion,

suflicient to reduce the pour point .of the .oil, ofa linear .polymeric .material having .-a molecular weight of atleast 1000 whose chain unitsaredimethylene groups and N- aliphatic-2,5-pyrr olidinedione nuclei which form chain members with the dimethylene groups by linking through the 3 and 4 carbon atoms .of .the pyrrolidinedione nucleus, in which each dimethylene ,group has a hydrogen replaced by a member of the group consisting of aromatic and aromatic ether radicals and the N-aliphatic group contains at least 12 carbonatoms and consists of carbon and hydrogen.

3. A paraflin wax-containing hydrocarbon oil having incorporated therein a small proportion, sufficient to reduce the pour point of the oil, of a, linear polymeric material having -a molecular weight of at least 1000 whose chain units are di methylene groups and N-alkyl-2,5-pyrrolidinedione nuclei which form chain members with 'the dimethylene groups by linking through the *3 and 4 carbon atoms of the-pyrrolidinedione nucleus, in which each dimethylenegroup'has a hydrogen replaced by a member of the group consisting of aromatic and aromatic ether radicals and the N- alkyl groupcontains at least 12 carbon atoms.

4. A paraffin wax-containing hydrocarbon -oil having incorporated therein a small proportion, suflicient to reduce the pour point of the oil, ofa linear polymeric material having .a molecular weight of at least 1000 whose chain units are dimethylene groups and N-aliphatic-2,5-pyrrolidinedione nuclei which form chain members with the dimethylene groups by linking through the .3

and 4 carbon atoms of the pyrrolidinedione nucleus, in which each dimethylene group hasia hydrogen replaced by an aromatic radical and the N-aliphatic group contains at least 12 carbon atoms. I

5. A paraflin wax-containing hydrocarbon .oil having incorporated thereinaa small proportion, sufficient to reduce the pour point of the :oil, 10f a linear. polymeric material having a molecular weightyof at least 1.000 whose chain units are :di-

methylene groups and N-alkyl-2,5-pyrrolidinedione nuclei which form chain members with the dimethylene groups by linking through the 3 and 4 carbon atoms of the pyrrolidinedione nucleus, in which each dimethylene group has a hydrogen replaced by an aromatic radical and the N-alkyl group contains at least 12 carbon atoms.

6. A parafiin wax-containing hydrocarbon oil havin incorporated therein a small proportion, sufiicient to reduce the pour point of the oil, of a linear polymeric material having a molecular weight of at least 1000 whose chain units are dimethylene groups and N-aliphatic-2,5-pyrrolidinedione nuclei which form chain members with the dimethylene groups by linking through the 3 and 4 carbon atoms of the pyrrolidinedione nucleus, in which each dimethylene group has a hydrogen replaced by an aryl radical and the N aliphatic group contains at least 12 carbon atoms and consists of carbon and hydrogen.

'7. A parafiin wax-containing hydrocarbon oil having incorporated therein a small proportion, sufficient to reduce the pour point of the oil, of a linear polymeric material having a molecular weight of at least 1000 Whose chain units are dimethylene groups and N-alkyl-2,5-pyrrolidinedione nuclei which form chain members with the dimethylene groups by linking through the 3 and LIHUQQ WU" LRLWUL 4 carbon atoms of the pyrrolidinedione nucleus, in which each dimethylene group has a hydrogen replaced by an aryl radical of the benzene series and the N-alkyl group contains at least 12 carbon atoms.

8. A parafiin wax-containing hydrocarbon oil having incorporated therein a small proportion, sufficient to reduce the pour point of the oil, of a linear polymeric material having a molecular weight of at least 1000 whose chain units are dimethylene groups and N-octadecyl-2,5-pyrrolidinedione nuclei which form chain members with the dimethylene groups by linking through the 3 and 4 carbon atoms of the pyrrolidinedione nucleus, in which each dimethylene group has a hydrogen replaced by an aryl radical of the ben zene series.

9. A paraffin wax-containing hydrocarbon oil having incorporated therein a small proportion, sufiicient to reduce the pour point of the oil, of a linear styrene/N-octadecyl-maleimide polymer having a molecular weight of at least 1000.

10. A paraffin wax-containing hydrocarbon oil having incorporated therein a small proportion, sufficient to reduce the pour point of the oil, of a linear indene/N-octadecyl-maleimide polymer having a molecular weight of at least 1000 MELVIN A. DIETRICH.

and: UN HUUH- 

